• Molecules and Cells
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• v.41 no.5
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• pp.373-380
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• 2018

Synapses and neural circuits form with exquisite specificity during brain development to allow the precise and appropriate flow of neural information. Although this property of synapses and neural circuits has been extensively investigated for more than a century, molecular mechanisms underlying this property are only recently being unveiled. Recent studies highlight several classes of cell-surface proteins as organizing hubs in building structural and functional architectures of specific synapses and neural circuits. In the present minireview, we discuss recent findings on various synapse organizers that confer the distinct properties of specific synapse types and neural circuit architectures in mammalian brains, with a particular focus on the hippocampus and cerebellum.

• Restorative Dentistry and Endodontics
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• v.31 no.3
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• pp.203-214
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• 2006

Dental pulp is a loose, mesenchymal tissue almost entirely enclosed in the dentin. It consists of cells, ground substance, and neural and vascular supplies. Damage to the dental pulp by mechanical, chemical, thermal, and microbial irritants can provoke various types of inflammatory response. Pulpal inflammation leads to the tissue degradation, which is mediated in part by Matrix metalloproteinase leads to accelerate extracellular matrix degradation with pathological pathway We have now investigated the induction of MMPs and inflammatory cytokines by Lipopolysaccharide (LPS) control of inflammatory mediators by peroxisome proliferator-activated receptors (PPARs). Human dental pulp cells exposed to various concentrations of LPS ($1-10{\mu}g/ml$) revealed elevated levels of MMP-2 and MMP-9 at 24 hrs of culture. LPS also stimulated the production of ICAM-1, VCAM-1, $IL-1{\beta},\;and\;TNF-{\alpha}$. Adenovirus $PPAR{\gamma}\;(Ad/PPAR{\gamma})\;and\;PPAR{\gamma}$ agonist rosiglitazone reduced the synthesis of MMPs, adhesion molecules and pro-inflammatory cytokines. The inhibitory effect of $Ad/PPAR{\gamma}$ was higher than that of $PPAR{\gamma}$ agonist. These result offer new insights in regard to the anti-inflammatory potential of $PPAR{\gamma}$ in human dental pulp cell.

• Molecules and Cells
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• v.42 no.8
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• pp.589-596
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• 2019

${\beta}Pix$ is a guanine nucleotide exchange factor for the Rho family small GTPases, Rac1 and Cdc42. It is known to regulate focal adhesion dynamics and cell migration. However, the in vivo role of ${\beta}Pix$ is currently not well understood. Here, we report the production and characterization of ${\beta}Pix$-KO mice. Loss of ${\beta}Pix$ results in embryonic lethality accompanied by abnormal developmental features, such as incomplete neural tube closure, impaired axial rotation, and failure of allantois-chorion fusion. We also generated ${\beta}Pix$-KO mouse embryonic fibroblasts (MEFs) to examine ${\beta}Pix$ function in mouse fibroblasts. ${\beta}Pix$-KO MEFs exhibit decreased Rac1 activity, and defects in cell spreading and platelet-derived growth factor (PDGF)-induced ruffle formation and chemotaxis. The average size of focal adhesions is increased in ${\beta}Pix$-KO MEFs. Interestingly, ${\beta}Pix$-KO MEFs showed increased motility in random migration and rapid wound healing with elevated levels of MLC2 phosphorylation. Taken together, our data demonstrate that ${\beta}Pix$ plays essential roles in early embryonic development, cell spreading, and cell migration in fibroblasts.

• The Journal of Korean Physical Therapy
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• v.12 no.3
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• pp.415-432
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• 2000

In mammals. axotomy of peripheral nerve leads to a complex. These events include swelling of cell body, disappearance of Nissl substance. Proximal and distal axon undergoes a variable deriable degree of traumatic degeneration and wallerian degeneration, respectively. Nerve injury may result in cell death or regeneration. Molecular changes include proliferation of Schwann cells, upregulation of neurotropism, neural cell adhesion molecules and cytokine. Also growth cone plays an essential role in axon guidance through interaction of cytoskeleton. We review cellular and molecular events after nerve injury and describe nerve regeneration and associated proteins.

• Molecules and Cells
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• v.39 no.10
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• pp.762-767
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• 2016

Fasciclin II (FasII), the Drosophila ortholog of neural cell adhesion molecule (NCAM), plays a critical role in synaptic stabilization and plasticity. Although this molecule undergoes constitutive cycling at the synaptic membrane, how its membrane trafficking is regulated to ensure proper synaptic development remains poorly understood. In a genetic screen, we recovered a mutation in Drosophila mical-like that displays an increase in bouton numbers and a decrease in FasII levels at the neuromuscular junction (NMJ). Similar phenotypes were induced by presynaptic, but not postsynaptic, knockdown of mical-like expression. FasII trafficking assays revealed that the recycling of internalized FasII molecules to the cell surface was significantly impaired in mical-like-knockdown cells. Importantly, this defect correlated with an enhancement of endosomal sorting of FasII to the lysosomal degradation pathway. Similarly, synaptic vesicle exocytosis was also impaired in mical-like mutants. Together, our results identify Mical-like as a novel regulator of synaptic growth and FasII endocytic recycling.

• Journal of Korean Neurosurgical Society
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• v.60 no.4
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• pp.417-423
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• 2017

Objective : Repair of sensorial nerve defect is an important issue on peripheric nerve surgery. The aim of the present study was to determine the effects of sensory-motor nerve bridging on the denervated dermatomal area, in rats with sensory nerve defects, using a neural cell adhesion molecule (NCAM). Methods : We compared the efficacy of end-to-side (ETS) coaptation of the tibial nerve for sural nerve defect repair, in 32 Sprague-Dawley rats. Rats were assigned to 1 of 4 groups : group A was the sham operated group, group B rats had sural nerves sectioned and buried in neighboring muscles, group C experienced nerve sectioning and end-to-end (ETE) anastomosis, and group D had sural nerves sectioned and ETS anastomosis was performed using atibial nerve bridge. Neurological evaluation included the skin pinch test and histological evaluation was performed by assessing NCAM expression in nerve terminals. Results : Rats in the denervated group yielded negative results for the skin pinch tests, while animals in the surgical intervention groups (group C and D) demonstrated positive results. As predicted, there were no positively stained skin specimens in the denervated group (group B); however, the surgery groups demonstrated significant staining. NCAM expression was also significantly higher in the surgery groups. However, the mean NCAM values were not significantly different between group C and group D. Conclusion : Previous research indicates that ETE nerve repair is the gold standard for peripheral nerve defect repair. However, ETS repair is an effective alternative method in cases of sensorial nerve defect when ETE repair is not possible.

• The Journal of Korean Physical Therapy
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• v.19 no.2
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• pp.41-55
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• 2007

Purpose: This study aimed to compare the effect on nerve regeneration of ultrasound irradiation in rats with peripheral nerve injury. Methods: To investigate alterations of the NCAM immunoreactivity in non-crushed part and crushed part of the spinal cord, the unilateral sciatic nerve of the rats were crushed. The expression of NCAM was used as the marked of peripheral nerve regeneration, and also plays an important role in developing nerve system. Experimental animals were sacrificed by perfusion fixation at post-injury 1, 3, 7, 14 days after ultrasound irradiation. The pulsed US was applied at a frequency of 1MHz and a spatial average-temporal average Intensity of 0.5W/of (20% pulse ratio) for 1 mins. The Luxol fast blue-cresyl violet stain were also done to observe the morphological changes. Results: Alteration of NCAM immunoreactivity in the crushed part and the non-crushed part of lower lumbar spinal cord were observed. NCAM-immunoreactivity cells were some increased in the dorsal horn lamina I, III and cell ventral horn at 1 day after unilateral sciatic nerve injury. However, there was not significant difference in the relationship between crushed part and non-crushed part. NCAM-inmmunoreactivity was remarkably increased at 3 days after unilateral sciatic nerve injuryin the gray matter and white matter. NCAM-immunoreactivity was increased in the ventral horn and post horn of experimental crushed part. Also, NCAM-immunoreactivity in large motor neurons in ventral horns lamina VIII, IX were increased at 7 days after unilateral sciatic nerve injury. At 14 days after sciatic nerve crushed injury, there was no significant difference. All group were decreased for 14 days. In the time course of NCAM expression, all groups showed a significant difference at 3day groups(p<0.05). Whereas, CC group was noted a significant difference between 3day and 7 day group respectively. In NCAM expression, there were significantly increased in all group. In the relationship between CNC group and ENC group, significant difference was detected among 3, 7, 14 day group(p<0.05). The difference between CC group and ENC group were noted in all groups(p<0.05). Conclusion: It is consequently suggested that the effects of the ultrasound irradiation may increase the NCAM immunoreactive neurons and glial cell in the spinal cord after unilateral sciatic nerve crushed injury. Therefore, the increased NCAM immunoreactivity in the spinal cord may reflect the neuronal damage and healing process induced by a ultrasound irradiation after peripheral nerve injury in rat.

• Polymer(Korea)
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• v.35 no.1
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• pp.7-12
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• 2011

Poly(lactic-co-glycolic acid) (PLGA) is a biodegradable synthetic polymer with acceptable mechanical strength and well-controlled degradation rate. Also, it can be easily fabricated into many shapes. Silk fibroin contains powerful bioactive molecules. We fabricated natural/synthetic hybrid films using 0, 10, 20, 40 and 80 wt% of silk fibroin. Schwann cells (SCs) were seeded on PLGA/silk fibroin hybrid films and confirmed the effects of adhesion and proliferation on SCs according to the content of silk fibroin. In this study, we confirmed PLGA/silk fibroin hybrid film containing 40% and 80% of silk fibroin interrupted adhesion and proliferation of SCs. Films containing 10% and 20% of silk, however, provided suitable environment for growth and proliferation of SCs. These results suggest that silk fibroin provides suitables surface to neural cells and its proper content provides proper culture conditions to improve cell adhesion and proliferation.

• Advances in pediatric surgery
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• v.8 no.1
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• pp.41-47
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• 2002

Abnormal distribution of the enteric nerves such as adrenergic, cholinergic and peptidergic nerves may cause the functional obstruction in Hirschsprung's disease (HD). Although the sustained contraction of the aganglionic segment is the main pathophysiology of HD, the etiology and pathogenesis is not thoroughly understood, With the recent progress of molecular biology and genetics,a more detailed approach to the pathogenesis of the HD can be undertaken. In this review, the roles of the nitric oxide, nitric oxide synthase and interstitial cells of Cajal on smooth muscle relaxation, the effects of extracellular matrix, cell adhesion molecules, neurotrophic factors on the migration and maturation of the neural crest cells are described. In the section of genetic factors, familial occurrences, association of chromosomal abnormalities, RET gene, glial cell line-derived neurotrophic factor gene, endothelin-3 gene and endothelin-B receptor gene and their r elationships to HD is briefly reviewed.